This invention relates to surgical instruments and assemblies.
The invention is more particularly concerned with surgical instruments for use in tracheostomy.
Where it is necessary to provide an emergency airway via a tracheostomy, or to enable a suction catheter to be introduced to the trachea or bronchial passages, this can be achieved by means of a relatively small diameter, uncuffed tracheostomy tube which does not hinder airflow to the patient s mouth and which enables the patient to cough and clear sputum normally.
The procedure is carried out by making a stab cut with a short-bladed scalpel through the neck into the trachea in the region of the cricothyroid membrane. The scalpel is then removed and the tracheostomy tube is inserted through the cut by means of an introducer with a tapered tip that projects from the patient end of the tube. Subsequently, the introducer is pulled rearwardly out of the machine end of the tube, leaving the tube in place to provide an air passage into the trachea.
In an alternative technique (The Seldinger technique), the cricothyroid membrane is pierced using a hollow needle after having first made an incision through the skin with a scalpel. A guide wire is then inserted through the needle into the trachea, the needle subsequently being withdrawn to leave the guide wire preserving access to the trachea. A dilator may then be fed over the guide wire to enlarge the opening into the trachea so that a tracheostomy tube can be introduced by sliding it over the dilator. Both the guide wire and the dilator are then withdrawn leaving the tube in position.
This technique has the advantage that the guide wire maintains the patency of the tracheostomy until the tracheostomy tube is inserted. There can otherwise be the tendency for the different layers of tissue in the neck to become displaced, especially if the patient should cough, making it difficult for the surgeon to insert the tracheostomy tube.
There is a disadvantage, however, with this technique in that it is possible for the needle to be pushed too far into the neck leading to possible damage to the posterior wall of the trachea. It is also possible that the needle could be pushed through the posterior wall of the trachea into the oesophagus; this could lead to the tracheostomy tube being inserted into the oesophagus rather the trachea.